To what extent do you agree: I want to adopt this equation for measuring the coast redwood.

I'm trying to wrap my head around the issues, explicit and implicit, in your new approach to volume for species like redwoods. So, here goes. The starting point for me is your discussion of competing forms: (1) a redwood that we interpret to be a main stem plus one or more coppice shoots that have fused to the main stem with a separation at below 1/3rd the height of the main stem, and (2) what we interpret as a single stem that then divides into two stems at 1/3rd or more of the height of the taller stem. As I understand your point, in the case of (1), we expect these coppice stems to increasingly fuse to the main stem and the bark to grow around the assemblage so that the fused region is indistinguishable from a single trunk to the naked eye. Many of the redwood giants are of this form. From this starting point, I understand that you wanted to develop a method to compute a "functional volume" for (1) versus (2), principally to establish parity for big tree competition purposes. So one challenge became how to compensate for the extra stems in a way that balances the factors. One consideration was how the tree might have developed had it continued as a single trunk. So, how do we reduce complex forms to single-trunk equivalents, doing justice to both? We've not been blind to these issues as we continue to work on the American Forests measuring guidelines, but we had not considered the approach that you outlined.

In your equations, where you show the expression V1 + V2 for what is treated as a single-trunk form (split occurs at or above 1/3rd the height of the tallest stem), I assume that you actually calculate the volume of each stem above the split and then add the single stem portion below the split. Or do you mean to do the actual volume calculation as though two stems were involved below the area of separation? Under the first approach, we might express the total volume symbolically as V1 + V2 + V3, where V1 and V2 are the stem volumes above the separation and V3 is the single trunk portion. In the case where the form is considered to be two trunks (separation at below 1/3 the height of the tallest stem) all the way down to near the base, V1 and V2 would represent the whole volumes of those stems. In the latter case, you then discount part of V2 per your 3(S/H) factor. As I understand it, you arrive at V1 and V2 by using the cross-sectional areas of the stems at separation. I presume that you first computed the volume below separation as a single trunk, i.e. V3, and then calculated V1 and V2 as: V1 = V3(A1/(A1+A2)) and V2 = V3(A2/(A1+A2)). The volume of V2 is then adjusted, using your factor. We might create a 4th variable V4: V4 = 3(V2)(S/H). Is this the way you do the calculations?

The reason I ask is that for many eastern trees, the line of separation distinguishing the individual trunks remains discernible, except for maybe a small section near the base. This allows us to measure the individual diameters of the trunks and compute V1 and V2 separately, as opposed to an apportioning strategy from a whole. We would likely do this if we considered the trees to be separate individuals as opposed to a coppice. We would determine which of the two possibilities (a coppice or separate trees) using the pith test. Given the size of redwoods and their giant forms, I expect that pith tests are pretty much out of the question.

Now for some history. When we began rewriting the American Forest measuring guidelines, we wanted to correct a big problem with the then system. As you know, the National Register had become saturated with multi-stem forms, often clearly more than one tree. We wanted the best of the single-trunk specimens to receive the attention they deserved. Don's pith test was a cornerstone for determining if a candidate was one or more trees. However, this left species prone to coppicing like redwoods, cottonwoods, silver maples, willows, live oaks, etc. in an in-between state. We didn't want to discredit these forms (Don's Gobsmackers), but were unsure of how to handle specimens where coppicing was at the root collar. This is still the case for the complicated forms like live oak. We continue to test different strategies.

One point I make for the group of readers as a whole. Suppose we have a clump of individual stems that are fused, but separate out at some point. We can compute the cross-sectional area of each at the location where all the stems have split from each other. We can compute each cross-sectional area as a percentage of the whole and then apply the each percentage the cross-sectional area where all stems have fused at a lower point on the trunk, ideally 4.5 feet above the ground. However, we might have to go lower, wherever. This allows us to treat each fused trunk separately in subsequent calculations. For example, following Zane's redwood method, we could discount the area or volume contribution for each of the coppice stems.

There are hurdles to be faced, and they are what we will continue working on. For example, if the two trunks of a coppice are touching, but individually discernible, we would want to calculate cross-sectional areas at various points of measurement (and subsequent volumes) separately as opposed to apportioning them via the above method. It is only if we cannot distinguish where one trunk stops and another starts that we would resort to the apportioning method.

Here is something else we want to keep in mind. It occasionally has relevance where attempting to deal with a total cross-sectional area of a fused pair versus handling them separately.

If A1 = area of one trunk of diameter D1 A2 = area of a second trunk of diameter D2 A = area of a trunk of diameter D, where D = D1 + D2 Then A - (A1+A2) = (PI/2)(D1)(D2). This expression quantifies the amount that the larger single trunk exceeds the sum of the two smaller ones subject to the constraint D = D1+D2. I realize that the actual trunks are compressed together, so the actual geometry doesn't fit exactly.

Bob

Robert T. LeverettCo-founder and Executive DirectorNative Native Tree SocietyCo-founder and PresidentFriends of Mohawk Trail State Forest

Everthing else you point out seems to make sense. My reasoning as to why I want to treat the two trunks as separate is simply to allow for trunks of different ages.

Steve Sillett published a study May 2015 that included a 3-trunked fusion. The ages of the three trunks were 820, 790, and 290. The tree is distinctly a fusion and though the three trunks are not the same age, they should still be considered measurement-worthy.

Also, DNA in regards to redwoods becomes extremely problematic. Redwoods can produce coppice shoots and also adventitious shoots. That being said, two trees that appear to be separated at the base could still be genetically identical. In a similar way, redwoods are such large, old-lived organisms that they have many mutations enough to completely change their genetic identity. There are other situations where entire groves are genetically identical. But what really matters is the morphology and development that is next to impossible with very old trees/clones (clones from a developmental sense, not a genetic sense).

Zane-An excellent discussion, and a potential direction for us to flesh out. I'm not familiar with the May 2015 study...do you happen to have a citation for it easily at hand? I'd love to see it!Thanks,-Don

It was with no surprise that I read that the coast redwood tree measuring community is ‘stumped’ with the conundrum of determining what is an" individual tree". Bob and I struggled for more than two years to arrive at a solution. Your initial post in the NTS BBS showed a lot of thought and it’s taken me several readings to get my head around it, and then I still have questions.

Part of my confusion comes from finding the right words to describe what we all mean. The other thing is we have been wearing our AF Measuring Guidelines Working Group hats for so long that we have to remember that we share words and phrases that may not fully mesh with your usages.

And another point of potential confusion...when speaking of national champion trees, we speak of their 'bigness' in terms of formula points from a configuration of height, circumference, and crown spread units. When the redwood measuring community speaks of giants, it's measure is volume, with base, iterations, adventitious branching, etc. in units of cubic feet, or meters.

My academic preparation is neither as recent, nor as specific as yours, so please excuse me if I express what may seem to be simplistic views. When you say fusion, can I assume that you are referring to two trees (in this case, of same species) that grew from separate sources (whether seeds, burls, etc.) in close enough proximity that they physically “met”, then extruded cambium/phloem away from contact zone….and then in the process of growing upwards, also grew “together” with bark enclosing the base in a manner that it’s difficult to assess, after significant time passage, that it was in fact two stems?

If that’s the case, then your formula for Volume Calculation makes sense to me, at least in that the formula would approximate what each stem ‘offered’ in the way of total volume, proportioned by respective cross-sectional areas, in your case, at the 1/3 total height level.Given that the proportion at that level is representative of the base proportions, this solves the problem of making sense out of the base, which may be obfuscated by centuries of growth around the two stems. To the extent that such measurements at 1/3 total height (or wherever the two stem emerge) are possible either by direct measurement accomplished by tree climbers, or remotely by reticled monocular/binocular, this has great promise.

It would seem to get messy down below, with ‘wood’ extruding away from contact zones in somewhat irregular fashion, but certainly a better estimate than any other I can envision short of an arboristic ultrasound mapping of tree densities…I have seen them used on ‘normal’ sizes of trees, but would imagine that they’d have to power up their analytics, and lengthen their circumferential band of signals.

If I have “barked up” the right tree in my read on your post, it would be consistent with what we in the Measuring Guidelines Working Group at American Forests are endorsing, in trying to differentiate single-stem trees from multiple-stemmed trees.

In no small part, this is a physiologically-based differentiation, in that assumptions come from plant physiology…in the case of gymnosperms and angiosperms, “a” tree is grown from “a” seed, the a single apical meristem extends upward, and with each successful growth increment creates a concentric annual (most of the time) ring. Subsequent growth years leave behind a pith, as the apical meristem ‘points the way’ upward, repeating the annual increment in an eventual series of nested annual rings.

Drawing from the Wood Science I was taught at Humboldt, the primary assumption is that trees, in the absence of external input, will grow up straight and with as near circular a cross-section as they can. Most of affecting external outputs can be seen, detected or inferred (soil movement, obstacles within proximity, canopy openings, gravity, etc.). Recalling how gymnosperms and angiosperms respond with compression wood and tension wood respectively, provides the observer/delineator with cues to the alignment of the pith relative to the eccentricity of the cross-section.

In a reverse-sort-of-logic manner, taking your cones diagrammed in your post, and running an assumed central axis (where pith would be, unless external input were noted) that went from vertex to the base (both equiangular and equidistant), one can make a reasonable guess how far away the pith lines would be at ground level.

Wouldn’t these be representative of the distance between their two seed sources?

In response to defining a fusion, we cannot know whether or not the fusion came from a single seed or not. There are situations, such as with Lost Monarch, that the fused trunk appears to angle inward toward the main trunk's pith below the split. There are other situations, such as with Melkor, where the two trunks appear to be extremely vertical and may not have originated from the pith.

As far as papers, in 1998, Peter Del Tredici published a paper Lignotubers in Sequoia sempervirens: development and ecological significance in Madroño. Steve Sillett's recent paper in May 2015 is How do tree structure and old age affect growth potential of California redwoods? in Ecological Monographs. If any access is needed to those papers, please let me know.

In Del Tredici's paper (along with a paper I am working on publishing very soon), we learn that sprouts in redwoods develop very similarly to epicormic branches just at the very base of the tree. The lignotubers from from a seed and the meristematic tissue is created at germination. The release of these meristems can be centuries after they first formed.

Similarly, we know from albino redwoods that redwoods have to produce adventitious shoots originating from their roots. That means that even a tree that originated 10 feet away (maybe even 20 or 30 feet away) could be from the same clone. There are genetic studies showing this to be the case.

So just following where the two piths are formed will not provide an answer. If the pith formed from either the lignotuber as a "branch" or from a root as an "adventitious branch," either way, developmentally, these are "branches." These branches, however, can become treelike.

With coast redwoods, especially in Prairie Creek and Del Norte County, they rarely produce seeds (as per Sillett and Van Pelt and personal observation). The seeds would have little chance of establishment with all the 8 foot tall sword ferns. So we can't, without genetic testing described in a recent paper published in March 2015, determine whether or not a redwood tree offspring is a clone (developmentally originating from the same seed) or aclonal (originating from an individual seed).

So again, coming from a point of "field work," we need to have a way to easily distinguish trees. And physiologically, even if the trees are aclonal within the fusion, they certainly are sharing resources and act physiologically like one. And in either situation, the tree's circumstances should be the same regardless of development from the same seed or different seeds.

Actually, I think people can spin their wheels on this one, if we are going to talk Coast Rewoods, and DNA will be involved.

It's most likely that the parks will NOT grant a permit to take DNA samples for something like this. The funding probably wouldn't even matter.

Round vs. ellipitical isn't a tried and true thought. Trees can easily grow elliptical due to reach and volume of roots on certain sides, lean, etc.. What would really make a fusion, is a clear and obvious fusion. I think something like Screaming Titans would be crystal clear. If Del Norte Titan were a fusion, then it would be theoretical.

For Del Norte Titan, the thought of DNA may go out the window, because, for example, the giant root sprout next to Lost Monarch could have originated from the roots of El Viejo Del Norte, or one of several other adjacent redwoods. Or ... others that were there, that are there no longer.

So I see this as a long amusing discussion, but not one of practical implementation.

yofoghorn wrote: snip ... A single-stemmed tree versus a fusion would likely have a smaller ground footprint making both nutrients collected from the ground and structural integrity a bit harder to manage once a trunk gets big. For the coast redwood, from a stability standpoint and from a nutrient standpoint, fusions are an advantage. But this is not good for the notable single stems. Why should we discount large 30000 cubic foot trees like Howland Hill Giant, an undisputed single-stem redwood, by adding up all the volume of fusions?

1. Howland Hill Giant is an "undisputed" single stem". Undisputed by who? Personally, I see it more looking single stem, but it could easily have a small fusion or two blended in there 1200 years ago, that we can't see visual evidence for. Just because we can't see something obvious, is not a guarantee it is not a fusion.

2. If I'm reading this right, it seems to say that fusions have a stability advantage. I disagree. We've seen ancient redwoods blow over, and it reveals the more or less deteriorated underside of the root system. Mathematically, the weight becomes too great for tissue to grow and expand. Trees can exert up to about 170 lbs. per square inch during growth. Old redwoods downward weight eventually over-powers that. Even a single trunk. So with fused stems, not only is the underside going to decline, but at some point the two or more trunks can add the disadvantage of poor root development in-between the two trunks. When two trunks are side by side, it really limits root and trunk development in between. I see them every bit as vulnerable, Maybe more vulnerable.

mdvaden wrote:Actually, I think people can spin their wheels on this one, if we are going to talk Coast Rewoods, and DNA will be involved.

It's most likely that the parks will NOT grant a permit to take DNA samples for something like this. The funding probably wouldn't even matter.

Round vs. ellipitical isn't a tried and true thought. Trees can easily grow elliptical due to reach and volume of roots on certain sides, lean, etc.. What would really make a fusion, is a clear and obvious fusion. I think something like Screaming Titans would be crystal clear. If Del Norte Titan were a fusion, then it would be theoretical.

For Del Norte Titan, the thought of DNA may go out the window, because, for example, the giant root sprout next to Lost Monarch could have originated from the roots of El Viejo Del Norte, or one of several other adjacent redwoods. Or ... others that were there, that are there no longer.

So I see this as a long amusing discussion, but not one of practical implementation.

Yeah, this is a long discussion with no "right" answers. The question still remains, however, how does one classify fusion versus non-fusion? There are trees that are middle-ground between one and two "trunks" and those trees, after more centuries of growth, could easily become one trunk trees. So aside from large trees that are "questionable" like Del Norte Titan, for example, what are your thoughts on trees that are middle ground. Attached is a photo of one of the trees that would "qualify" for the formula I present. What is it? It's not a "double," but it might not be a bonafide "single" either. This is the whole purpose of the formula, to try and get a fair assessment for the redwoods that do not fit our "boxes."

yofoghorn wrote:Yeah, this is a long discussion with no "right" answers. The question still remains, however, how does one classify fusion versus non-fusion? There are trees that are middle-ground between one and two "trunks" and those trees, after more centuries of growth, could easily become one trunk trees. So aside from large trees that are "questionable" like Del Norte Titan, for example, what are your thoughts on trees that are middle ground.

I think it may boil down to opinion.

Trees can do such odd things, like the Corkscrew Tree, it seems a real possibility that an absolute single stem redwood could disfigure or alter its shape over centuries and develop what to one's eye would seem to be likely fusion. May not be the norm, but it seems withing the realm of possibilities.